Figure 2.1. Categorized conventional robotic joint mechanisms applied to the current hydraulically actuated robots. (a) CJ-1: linkage-driven joint mechanism, (b) CJ-2:... 42

Figure 2.2. Current hydraulically actuated robots. (a)~(e): quadrupedal robots[1-5], (f)~(j): humanoids[6-10], and (k)~(o): robotic arms. 43

Figure 2.3. The major drawback of the linkage-driven joint mechanism. (a) the schematic diagram, and (b) the τ-q graph corresponding result from Equation (2.1)... 45

Figure 2.4. Categorized conventional robotic wrist mechanisms applied to the existing hydraulically actuated robotic arm. (a) CW-1: serial-chain wrist and (b) CW-2:... 48

Figure 3.1. Schematic image of two antagonistic configurations. 1) proposed robotic joint mechanism, THoR Joint (left side), and 2) biological antagonistic muscle pairs... 51

Figure 3.2. Comparative schematic images of two robotic joint mechanisms. (a) Linkage-driven robotic joint mechanism with linkages and a double-acting linear... 53

Figure 3.3. Comparison τ-q graphs of two robotic joint mechanisms. (a) Linkage-driven robotic joint mechanism, (b) Proposed robotic joint mechanism, THoR Joint. 54

Figure 3.4. Schematic images of two varieties of tendon-driven robotic joint mechanisms which are categorized by the literature[16]. (a) 1N configuration and (b)... 55

Figure 3.5. Comparison between (a) the conventional 1N configuration[17-19] and (b) the proposed THoR configuration for pneumatic/hydraulic actuated tendon-... 56

Figure 3.6. Comparison between (a) the conventional 2N configuration[20-23] and (b) the proposed THoR configuration for pneumatic/hydraulic actuated tendon-... 57

Figure 3.7. Factors degrading force control performance in conventional hydraulically actuated robotic joint mechanisms. (a) Backlash and clearance and (b) Internal leakage. 58

Figure 3.8. Conceptual mechanical design of the THoR Joint with its components, including the Hydraulic Power Unit (HPU), a pulley, two tendons, tendon mounting... 60

Figure 3.9. Mechanical design overview of THoR Joint. (a) Detailed mechanical design of the THoR Joint, (b) Exploded view of the tend on mounting mechanism for... 62

Figure 3.10. Schematic images of THoR Joint configuration (a) without and (b) with the proposed wire mounting hook and fixed point adjustable pulley. 65

Figure 3.11. Description of adjustable functionality for the tend on mounting position of the proposed tendon mounting mechanism. (a) Side and sectional view of the... 67

Figure 3.12. Isometric and bottom view of the integrated HDU with transparent manifold and internal PT and AB passages. 69

Figure 3.13. Fabricated THoR Joint and its application. (a) The first version of 1-DoF THoR Joint, (b) The second version of 1-DoF THoR Joint, (c) 3-DoF robotic... 70

Figure 3.14. Comparative analysis of RoM and torque density between the conventional robotic joint mechanisms, linkage-driven joint mechanism (CJ-1) and... 73

Figure 3.15. Overall control architecture. (a) 1-DoF THoR Joint, and (b) 3-DoF robotic arm. 76

Figure 3.16. Experimental result of joint position control performances at frequencies of 0.5, 1.0, and 1.5 Hz. 78

Figure 3.17. Experimental result of joint torque control performances: (a) Zero torque tracking test, (b) Gravity compensation test. 80

Figure 3.18. Comparative analysis of reachable workspace between the conventional and proposed robotic arm for mobile manipulation platforms. (a) HyQequipped with... 82

Figure 3.19. Door opening task execution, which was performed sequentially according to the arrows. 84

Figure 3.20. Valve locking task execution. (a) zoom-out image, (b) zoom-in images where the task was performed sequentially according to the arrows. 84

Figure 3.21. Experimental procedures of direct teaching. (a) Two sequential steps: (1) demonstration-based teaching by the human operator, (2) imitation-based fol-... 85

Figure 3.22. Experimental results of direct teaching. Three-row graphs show the angle of the joint 1,2, and 3 during imitation-based following, respectively. 86

Figure 4.1. Schematic image of two 3-DoF wrist configurations. 1) the proposed wrist mechanism (left side) with forearm pronation and supination (denoted as a... 90

Figure 4.2. Comparative example of performing a grasping task in narrow spaces. (a) a human arm, (b) a robotic arm (Note: These illustrations are adapted from... 91

Figure 4.3. Detailed mechanical design overview of THoR Wrist. 94

Figure 4.4. Detailed mechanical design of 2-DoF URD and WFE joint mechanism with mechanical components, i.e., tendons, rollers, pulleys. 96

Figure 4.5. The first motion-coupled problem: Motion-coupled problem occur at joint 3 caused by joint 2 motion. 97

Figure 4.6. The second motion-coupled problem:Motion-coupled problem occur at joint 2 caused by joint 3 motion. 98

Figure 4.7. A free-body diagram of 2-DoF URD and WFE joint mechanism when the second motion coupled problem occurs. 100

Figure 4.8. Detailed mechanical design of 1-DoF FPS joint mechanism. 101

Figure 4.9. Proposed rotary union for 1-DoF FPS joint mechanism. 101

Figure 4.10. Proposed rotary union for 1-DOF FPS joint mechanism. 102

Figure 4.11. Definition of each segment and the corresponding joint axes, and sizes of a human wrist, THoR Wrist, and DSPM wrist with the same forearm length. 104

Figure 4.12. Visualized comparative analysis results of orientation workspace and reversed workspace between a human wrist, THoR Wrist, and DSPM Wrist. (a)-(c)... 112

Figure 4.13. Visualized comparative analysis results of manipulability measure between a human wrist, THoR Wrist, and DSPM Wrist. (a)-(c) 3D manipulability... 113

Figure 4.14. Overall control architecture for 3-DoF fabricated THoR Wrist. 116

Figure 4.15. Experimental results of 0.5 Hz sinusoidal position tracking tests. (a) The first sinusoidal position tracking test without the motion-coupled problem. (b)... 117

Figure 4.16. Experimental results of gravity compensation test without the motion-coupled torque compensation. (a) and (b) represent the snapshots during 0~1 sec... 119

Figure 4.17. Experimental results of gravity compensation test with the motion-coupled torque compensation. (a), (b), (c), and (d) represent the snapshots during... 120

Figure 5.1. Schematic image of the proposed 6-DoF hydraulically actuated robotic arm, THoR Arm. It is integrated with the proposed joint mechanism, THoR Joint,... 124

Figure 5.2. Two conventional robotic applications for heavy handling for industrial workers. (a) Exoskeleton, and (b) Lift Assist Device. 125

Figure 5.3. Mechanical system overview of THoR Arm with its joint configuration and dimensions. 127

Figure 5.4. Comparison of transmission and actuator configurations for tendon-driven robotic arms. (a) conventional tendon-driven robotic arms (transmission: 130

Figure 5.5. Comparative analysis procedures of reachable workspace volume and payload density between the 6-DoF conventional robotic arms and the 6-DoF pro-... 133

Figure 5.6. Comparative analysis result of reachable workspace volume and payload density between the 6-DoF conventional robotic arms, Grips (CA1), HyArm (CA2),... 137

Figure 5.7. Comparative simulation results regarding the manipulation tasks in narrow spaces. (a) THoR Arm (success), (b) DSPM Arm (fail). 138

Figure 5.8. Overall control architecture for 6-DoF fabricated THoR Arm. 140

Figure 5.9. Schematic experimental scenario of handling heavy objects with an operator. (a) Tire assembly task where an operator works together with the robotic... 142

Figure 5.10. Snapshots of the experimental scenario involving the handling of heavy objects, including moving a 20 kg tire, aligning the tire on an axis of a mount, and... 143

Figure B.1. Link frame definition of the proposed robotic arm. (a)With the schematic robotic arm, and (b) Without the schematic robotic arm. 160

Figure B.2. Link segment definition of the proposed robotic arm with the corresponding inertia frames of each link. (a) Link 1, (b) Link 2, and (c) Link 3. 162

Figure B.3. Link frame definition of the proposed robotic arm designed for mobile manipulation platform, JINPOONG-II. 163

Figure B.4. Link segment definition of the proposed robotic arm designed for mobile manipulation platform, JINPOONG-II. (a) Base, (b) Link 1, (c) Link 2, (d) Link 3,... 165

Figure B.5. Frame definition of a human wrist for calculating orientation workspace volume and manipulability measure. 168

Figure B.6. Frame definition of the proposed robotic wrist mechanism, THoR Wrist, for orientation workspace volume and manipulability measure. 168

Figure B.7. Frame definition of the conventional robotic wrist mechanism, DSPM wrist, for orientation workspace volume and manipulability measure. 169

Figure B.8. Frame definition of a human wrist for calculating reversed workspace distance. 169

Figure B.9. Frame definition of the proposed robotic wrist mechanism, THoR Wrist, for reversed workspace distance. 170

Figure B.10. Frame definition of the conventional robotic wrist mechanism, DSPM wrist, for reversed workspace distance. 170

Figure B.11. Link frame definition of the proposed robotic arm, THoR Arm. (a) With the schematic robotic arm, and (b) Without the schematic robotic arm. 171

Figure B.12. Link segment definition of the proposed robotic arm, THoR Arm. (a) Link 1, (b) Link 2, (c) Link 3, (d) Link 4, (e) Link 5, and (f) Link 6. 173